The proposed research will concentrate on the following objectives and methods: (a) Synthesis, purification and characterization of blocked isocyanate functions of 2, 4-tolylenediisocyanate (TDI), the mono adducts of TDI with hydroxyethyl methacrylate (HEMA) and TDI adducts of HEMA-methyl methacrylate (MMA) copolymers. (b) Study of the interaction of these blocked isocyanate functional adducts with dentin and enamel using attenuated total reflectance (ATR) in the infrared and scanning electron microscopy (SEM). (c) Formulation of selected blocked isocyanate functional materials into fast-setting adhesive systems. (d) Investigation of adhesion to dentin and enamel by destructive methods (shear and tensile tests) and examination of the mode of failure by SEM. (e) Measure tensile strengths, shear strengths and glass transition temperatures by known methods. Differential thermal analysis will be used to estimate glass transition temperatures.